<low profile subs> There isn't much depth behind the rear wall. Some people move it forward to get additional space. A few years ago, I had a local stereo shop install an 8" woofer in the lock box behind the driver's seat. They made a new lid for the box, cut out a speaker hole and covered the lid with gray speaker cloth. They used a tiny mixer to pull the bass equally off of both rear speakers, and added a small amp (both also in the box). They also added a capacitor circuit to filter out the bass frequencies from the rear speakers, but I think this could use some more tweaking. See http://www.passivecrossovers.com/section05.htm and http://www.ehow.com/ehow/ehowDetails.jsp?id=8448 The benefits are: - Less load on my stock radio - All the bass I could ever use - No loss of room on the rear shelf - No loss of bass if you put luggage on the rear shelf - Less rumble from the rear speakers (from too much bass) Bass is pretty non-directional, so the asymmetrical arrangement isn't a big problem. As with any well-designed speaker enclosure, the lock box has a rear opening via a baffle system. <GRIN> Gary (at) IN2TIME.com www.IN2TIME.com www.PNDC.org VIN 5612